media: vidtv: reinstate sysfs bind attrs

Reinstate sysfs bind attrs so that vidtv can be bound and unbound
via sysfs. This is useful for automated regression testing in
userspace.

Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>